Cutting "out" items from a sheet

[MrBean]

I've had my router up and running for a few days now, and it's working as it should. I am however having trouble cutting items out of the material. As opposed to machining away ALL the material to leave the part. I can't figure out how to cut for example, a clock gear "out" of the sheet instead of milling a big chunk of the sheet away to leave the gear.

What I'm doing now.

1 Create model in Rhino
2 Import model into Visualmill and create roughing & finishing pass G-code.
3 Load G-code into Mach2 and run program.

I have access to this software at work. Except Mach2, which I bought for use at home, but it's not my job at work to use it, so I am not at all familiar with it. I have learnt enough to make g-code from a model, which I e-mail to my home computer to run on Mach2.

Can anyone point me in the right direction or recommend some cheaper programs I can use at home.

It take ages to machine out a big square chunk of stock when I just want to cut "out" a circle.

Help.....Thanks...

Hope that made sense.

[High Seas]

Sorta sounds like you want to "trace" the gear (vector) and not "mill" it in x-y (raster) fashion, eh? MACH2 will import a dxf as a vector file and let you do that as I recall Is that a hint? [My terms may be off - but you'll get the idea I bet]
I've used a variety of other programs to generate the vector to gCode - so I'm not intentionally being cute here - just can't recall what I did last that worked so good!
For example ALGOLAB has a raster to vector that will let you save as a dxf and then import into MACH2, so there's a path, certainly others will have some clearer insights too. cheers - Jim

[MrBean]

I can load a dxf into mach2 but how do I tell it the depth I want to cut as the dxf will only be 2D? If the part is deep I'll want to do multiple passes to get to final depth. Can I tell it I want to do 3 passes or whatever?

I guess I'm in for a few hours of .pdf reading.

[Bloy2004]

In Mach2 there is a feature called "multi-pass". Here, when you select it, a dialog box pops up and asks for number of iterations (passes) and then depth of first pass and after that depth of each succeeding pass. Does this help?

[HomeCNC]

am however having trouble cutting items out of the material. As opposed to machining away ALL the material to leave the part.

It sounds like you are choosing the wrong machining strategy. To cut out a shape like a puzzle piece, you need to choose the strategy called "Profile". This is what most CAM software calls it. With profile, the cutter will follow the line you pick at a depth you tell it. Or it will do multiple passes. If you have cutter compensation on. You can tell the cutter to be on the Left, Right, or center of the line.

[jdwoods]

I'm a newbie
I plan on taking line drawings and using them to cut out designs. I am going to use Desk Art to convert drawings to G-Code. Is there a way to tell it or another program where to start and what to cut first?

[ger21]

DeskArt won't do what you want it to, I don't think (I just looked at the website). It basically turns a picture into a 3D object and machines the entire object.

If your drawing software can save as .dxf, you can use ACE ( http://www.dakeng.com ) to turn it in to g-code

[jdwoods]

Desk Art will convert files to .DXF as well. I dont know how to tell it what to cut first.

[ger21]

It creates ONE SINGLE .dxf mesh object. The entire object is cut, not individual lines. You need something that will cut individual lines. I don't think DeskArt can do that. This is what you're talking about, right? http://www.deskam.com/deskart.html

[The Wizard]

Originally Posted by jdwoods I'm a newbie I plan on taking line drawings and using them to cut out designs. I am going to use Desk Art to convert drawings to G-Code. Is there a way to tell it or another program where to start and what to cut first?

Have you looked at 'SheetCam'? That will do what you need and more. It can be found at:

http://www.sheetcam.com/

HTH,

Larry

[HuFlungDung]

Mr Bean,
I haven't seen VisualMill in use, but generally, a roughing procedure is designed to clean out all the material within a given profile. This is wasteful if you want to profile. I'm not knocking the advice that others have given you. Profile is the way to go.

But, for future reference, you may want to experiment with "roughing" by using a "Finishing" process. Generally, a finishing process will create sort of a profiling type of process where the cutter hugs the net shape of the model and will not clean out any excess stock that is more than the cutter diameter from the part.

If Visualmill has an option for a finish amount in the Finishing process, that is what you would use to keep the "rough-finish" pass away from the final product. Then, go at it again with only the Finishing process again, but with zero finish allowance.

[MrBean]

Thanks all for the advice. I've managed to get VM to do profiling with X amount of depth passes so I can cut stuff out from a sheet. Have been happily cutting pieces for a while now, and is working well.

Thanks all.

Regards Terry.....